Many low cut type socks are provided with an ornamental or decorative upper edge which is formed by a "shell" type of sewing stitch surrounding the upper edge. This decorative shell stitch top is usually formed of a yarn of different color from the yarn used in knitting the body of the sock. A special sewing machine is used and the operator must stitch completely around the upper edge of the sock to form the decorative shell stitch. The sewing of this overedge shell stitching requires a skilled operator and involves a separate step in the manufacture of the sock so that the cost of producing the sock is increased.